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  • Administer, manage, monitor, and fine tune the performance of your Oracle SOA Suite 11g Service Infrastructure and SOA composite applications.

    - by JuergenKress
    Key Features of the book If you are an Oracle SOA suite administrator, then this book is your bible. It gives you everything you need to know about all your tasks and help you to apply what you learn in your everyday life right from the first chapter. The book walks through promoting code across environments, performance tuning the service infrastructure, monitoring the environment, configuring security policies, managing the dehydration store, backing and restoring environments and so on. Packed with real-world examples from authors' own experiences, this books offers a unique insight into Oracle SOA Suite Administration. Detailed description The book begins with an introduction of SOA and quickly moves on to management of SOA composite applications. Readers will learn how to manage composite applications, their deployments and lifecycles. Equipped with this knowledge, readers will be introduced to monitoring and performance tuning SOA Suite, monitoring instances, messages, and composite applications, managing faults and exceptions, configuring audit levels of composite applications to include end-to-end monitoring through the use of extended logging as well as administering and configuring all SOA Suite components. A very important aspect of administration is tuning and optimizing the infrastructure for performance and book offers real work recommendations to monitor and performance tune service engines, the underlying WebLogic server, threads and timeouts, files systems, and composite applications. It also covers detailed administration of individual service components, configuring the infrastructure MBeans using both Oracle Enterprise Manager Fusion Middleware Control and WLST based scripts, migrating worklist preferences and BAM data across environments, setting up Email, LDAP and custom XPath. An administrator is always trusted with troubleshooting and root causing problems in the infrastructure and this book will help you through the troubleshooting approaches as how to identify faults and exception through extended logging and thread dumps and find solutions to common startup problems and deployment issues. The advanced contents of this book explains OWSM security framework and how to secure components deployed to the infrastructure along with the details of all groundwork needed to ready the environment. Last few chapters help you to understand and deal with managing the metadata services repository and dehydration store, backup and recovery and concluding with advanced topics such as silent/scripted installations, cloning, upgrading, patching and high availability installations. Packed with real-world examples, and tips straight from the trench; this book offers insights into SOA Suite administration that you will not find elsewhere. Part of our writing style in this book draws heavily on the philosophy of reuse and as such the book provide an ample of executable SQL queries and WLST scripts that administrators can reuse and extend to perform most of the administration tasks such as monitoring instances, processing times, instance states and perform automatic deployments, tuning, migration, and installation. These scripts are spread over each of the chapters in the book and can also be downloaded from here. The book is available in different formats at the following websites: Paperback and eBook versions & Kindle version. It is available for order and signed copies are available through our web site. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA book,SOA Suite Adminsitration,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • PASS: International Travels

    - by Bill Graziano
    Nihao!  One of the largest changes PASS is going through is the the expansion outside the US and Canada.  We’ve had international chapters and events in Europe since the early 2000’s.  But nothing on the scale we’re seeing now.  Since January 1st there have been 18 SQL Saturday events outside North America and 19 events in North America.  We hope to have three international SQLRally events outside the US in FY13 (budget willing).  I don’t know the exact percentage of chapters outside the US but it’s got be 50% or higher. We recently started an effort to remake the Board to better reflect the growing global face of PASS.  This involves assigning some Board seats to geographic regions.  You can ask questions about this in our feedback forum, participate in a Twitter chat or ask questions directly of Board members.  You can email me at if you’d like to ask a question directly.  We’re doing this very slowly and deliberately in hopes that a long communication cycle gives us a chance to address all the issues that our members will raise. After the Summit we passed a budget exception allocating an extra $20,000 for Board members to travel to local events.  I think it’s important for Board members to visit new areas and talk to more of our members.  I sent out an email asking where people had attended events outside their home city.  Here’s the list I got back: Albuquerque, Amsterdam, Boston, Brisbane, Chicago, Colorado Springs, Columbus, Dallas, Houston, Jacksonville, Las Vegas, London, Louisville, Minneapolis, New York City, Orange County, Orlando, Pensacola, Perth, Philadelphia, Phoenix, Redmond, Seattle, Silicon Valley, Sydney, Tampa Bay, Vancouver, Washington DC and Wellington.  (Disclaimer: Some of this travel was paid for by employers or Board members themselves.  Some of this travel may have been completed before the Summit.  That’s still one heck of a list!) The last SQL Saturday event this fiscal year is SQL Saturday Shanghai.  And that’s one I’m attending.  This is our first event in China and is being put on in cooperation with the local Microsoft office.  Hopefully this event will be the start of a growing community in China that includes chapters, SQL Saturdays and maybe a SQLRally or two in the future.  I’m excited to speak with people that are just starting down this path and watching this community grow. I encourage you to visit the PASS Global Growth site and read through the material there.  This is the biggest change we’ve made to our governance since I’ve been on the Board.  You need to understand how it affects you and how it affects the organization. And wish me luck on the 15 hour flight to Shanghai on Friday afternoon.  Rob Farley flies from Australia to the US for PASS events multiple times per year and I don’t know how he does it so often.  I think one of these is going to wipe me out.  (And Nihao (knee-how) is Chinese for Hello.)

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  • Remove box2d bodies after collision deduction android?

    - by jubin
    Can any one explain me how to destroy box2d body when collide i have tried but my application crashed.First i have checked al collisions then add all the bodies in array who i want to destroy.I am trying to learning this tutorial My all the bodies are falling i want these bodies should destroy when these bodies will collide my actor monkey but when it collide it destroy but my aplication crashed.I have googled and from google i got the application crash reasons we should not destroy body in step funtion but i am removing body in the last of tick method. could any one help me or provide me code aur check my code why i am getting this prblem or how can i destroy box2d bodies. This is my code what i am doing. Please could any one check my code and tell me what is i am doing wrong for removing bodies. The code is for multiple box2d objects falling on my actor monkey it should be destroy when it will fall on the monkey.It is destroing but my application crahes. static class Box2DLayer extends CCLayer { protected static final float PTM_RATIO = 32.0f; protected static final float WALK_FACTOR = 3.0f; protected static final float MAX_WALK_IMPULSE = 0.2f; protected static final float ANIM_SPEED = 0.3f; int isLeft=0; String dir=""; int x =0; float direction; CCColorLayer objectHint; // protected static final float PTM_RATIO = 32.0f; protected World _world; protected static Body spriteBody; CGSize winSize = CCDirector.sharedDirector().winSize(); private static int count = 200; protected static Body monkey_body; private static Body bodies; CCSprite monkey; float animDelay; int animPhase; CCSpriteSheet danceSheet = CCSpriteSheet.spriteSheet("phases.png"); CCSprite _block; List<Body> toDestroy = new ArrayList<Body>(); //CCSpriteSheet _spriteSheet; private static MyContactListener _contactListener = new MyContactListener(); public Box2DLayer() { this.setIsAccelerometerEnabled(true); CCSprite bg = CCSprite.sprite("jungle.png"); addChild(bg,0); bg.setAnchorPoint(0,0); bg.setPosition(0,0); CGSize s = CCDirector.sharedDirector().winSize(); // Use scaled width and height so that our boundaries always match the current screen float scaledWidth = s.width/PTM_RATIO; float scaledHeight = s.height/PTM_RATIO; Vector2 gravity = new Vector2(0.0f, -30.0f); boolean doSleep = false; _world = new World(gravity, doSleep); // Create edges around the entire screen // Define the ground body. BodyDef bxGroundBodyDef = new BodyDef(); bxGroundBodyDef.position.set(0.0f, 0.0f); // The body is also added to the world. Body groundBody = _world.createBody(bxGroundBodyDef); // Register our contact listener // Define the ground box shape. PolygonShape groundBox = new PolygonShape(); Vector2 bottomLeft = new Vector2(0f,0f); Vector2 topLeft = new Vector2(0f,scaledHeight); Vector2 topRight = new Vector2(scaledWidth,scaledHeight); Vector2 bottomRight = new Vector2(scaledWidth,0f); // bottom groundBox.setAsEdge(bottomLeft, bottomRight); groundBody.createFixture(groundBox,0); // top groundBox.setAsEdge(topLeft, topRight); groundBody.createFixture(groundBox,0); // left groundBox.setAsEdge(topLeft, bottomLeft); groundBody.createFixture(groundBox,0); // right groundBox.setAsEdge(topRight, bottomRight); groundBody.createFixture(groundBox,0); CCSprite floorbg = CCSprite.sprite("grassbehind.png"); addChild(floorbg,1); floorbg.setAnchorPoint(0,0); floorbg.setPosition(0,0); CCSprite floorfront = CCSprite.sprite("grassfront.png"); floorfront.setTag(2); this.addBoxBodyForSprite(floorfront); addChild(floorfront,3); floorfront.setAnchorPoint(0,0); floorfront.setPosition(0,0); addChild(danceSheet); //CCSprite monkey = CCSprite.sprite(danceSheet, CGRect.make(0, 0, 48, 73)); //addChild(danceSprite); monkey = CCSprite.sprite("arms_up.png"); monkey.setTag(2); monkey.setPosition(200,100); BodyDef spriteBodyDef = new BodyDef(); spriteBodyDef.type = BodyType.DynamicBody; spriteBodyDef.bullet=true; spriteBodyDef.position.set(200 / PTM_RATIO, 300 / PTM_RATIO); monkey_body = _world.createBody(spriteBodyDef); monkey_body.setUserData(monkey); PolygonShape spriteShape = new PolygonShape(); spriteShape.setAsBox(monkey.getContentSize().width/PTM_RATIO/2, monkey.getContentSize().height/PTM_RATIO/2); FixtureDef spriteShapeDef = new FixtureDef(); spriteShapeDef.shape = spriteShape; spriteShapeDef.density = 2.0f; spriteShapeDef.friction = 0.70f; spriteShapeDef.restitution = 0.0f; monkey_body.createFixture(spriteShapeDef); //Vector2 force = new Vector2(10, 10); //monkey_body.applyLinearImpulse(force, spriteBodyDef.position); addChild(monkey,10000); this.schedule(tickCallback); this.schedule(createobjects, 2.0f); objectHint = CCColorLayer.node(ccColor4B.ccc4(255,0,0,128), 200f, 100f); addChild(objectHint, 15000); objectHint.setVisible(false); _world.setContactListener(_contactListener); } private UpdateCallback tickCallback = new UpdateCallback() { public void update(float d) { tick(d); } }; private UpdateCallback createobjects = new UpdateCallback() { public void update(float d) { secondUpdate(d); } }; private void secondUpdate(float dt) { this.addNewSprite(); } public void addBoxBodyForSprite(CCSprite sprite) { BodyDef spriteBodyDef = new BodyDef(); spriteBodyDef.type = BodyType.StaticBody; //spriteBodyDef.bullet=true; spriteBodyDef.position.set(sprite.getPosition().x / PTM_RATIO, sprite.getPosition().y / PTM_RATIO); spriteBody = _world.createBody(spriteBodyDef); spriteBody.setUserData(sprite); Vector2 verts[] = { new Vector2(-11.8f / PTM_RATIO, -24.5f / PTM_RATIO), new Vector2(11.7f / PTM_RATIO, -24.0f / PTM_RATIO), new Vector2(29.2f / PTM_RATIO, -14.0f / PTM_RATIO), new Vector2(28.7f / PTM_RATIO, -0.7f / PTM_RATIO), new Vector2(8.0f / PTM_RATIO, 18.2f / PTM_RATIO), new Vector2(-29.0f / PTM_RATIO, 18.7f / PTM_RATIO), new Vector2(-26.3f / PTM_RATIO, -12.2f / PTM_RATIO) }; PolygonShape spriteShape = new PolygonShape(); spriteShape.set(verts); //spriteShape.setAsBox(sprite.getContentSize().width/PTM_RATIO/2, //sprite.getContentSize().height/PTM_RATIO/2); FixtureDef spriteShapeDef = new FixtureDef(); spriteShapeDef.shape = spriteShape; spriteShapeDef.density = 2.0f; spriteShapeDef.friction = 0.70f; spriteShapeDef.restitution = 0.0f; spriteShapeDef.isSensor=true; spriteBody.createFixture(spriteShapeDef); } public void addNewSprite() { count=0; Random rand = new Random(); int Number = rand.nextInt(10); switch(Number) { case 0: _block = CCSprite.sprite("banana.png"); break; case 1: _block = CCSprite.sprite("backpack.png");break; case 2: _block = CCSprite.sprite("statue.png");break; case 3: _block = CCSprite.sprite("pineapple.png");break; case 4: _block = CCSprite.sprite("bananabunch.png");break; case 5: _block = CCSprite.sprite("hat.png");break; case 6: _block = CCSprite.sprite("canteen.png");break; case 7: _block = CCSprite.sprite("banana.png");break; case 8: _block = CCSprite.sprite("statue.png");break; case 9: _block = CCSprite.sprite("hat.png");break; } int padding=20; //_block.setPosition(CGPoint.make(100, 100)); // Determine where to spawn the target along the Y axis CGSize winSize = CCDirector.sharedDirector().displaySize(); int minY = (int)(_block.getContentSize().width / 2.0f); int maxY = (int)(winSize.width - _block.getContentSize().width / 2.0f); int rangeY = maxY - minY; int actualY = rand.nextInt(rangeY) + minY; // Create block and add it to the layer float xOffset = padding+_block.getContentSize().width/2+((_block.getContentSize().width+padding)*count); _block.setPosition(CGPoint.make(actualY, 750)); _block.setTag(1); float w = _block.getContentSize().width; objectHint.setVisible(true); objectHint.changeWidth(w); objectHint.setPosition(actualY-w/2, 460); this.addChild(_block,10000); // Create ball body and shape BodyDef ballBodyDef1 = new BodyDef(); ballBodyDef1.type = BodyType.DynamicBody; ballBodyDef1.position.set(actualY/PTM_RATIO, 480/PTM_RATIO); bodies = _world.createBody(ballBodyDef1); bodies.setUserData(_block); PolygonShape circle1 = new PolygonShape(); Vector2 verts[] = { new Vector2(-11.8f / PTM_RATIO, -24.5f / PTM_RATIO), new Vector2(11.7f / PTM_RATIO, -24.0f / PTM_RATIO), new Vector2(29.2f / PTM_RATIO, -14.0f / PTM_RATIO), new Vector2(28.7f / PTM_RATIO, -0.7f / PTM_RATIO), new Vector2(8.0f / PTM_RATIO, 18.2f / PTM_RATIO), new Vector2(-29.0f / PTM_RATIO, 18.7f / PTM_RATIO), new Vector2(-26.3f / PTM_RATIO, -12.2f / PTM_RATIO) }; circle1.set(verts); FixtureDef ballShapeDef1 = new FixtureDef(); ballShapeDef1.shape = circle1; ballShapeDef1.density = 10.0f; ballShapeDef1.friction = 0.0f; ballShapeDef1.restitution = 0.1f; bodies.createFixture(ballShapeDef1); count++; //Remove(); } @Override public void ccAccelerometerChanged(float accelX, float accelY, float accelZ) { //Apply the directional impulse /*float impulse = monkey_body.getMass()*accelY*WALK_FACTOR; Vector2 force = new Vector2(impulse, 0); monkey_body.applyLinearImpulse(force, monkey_body.getWorldCenter());*/ walk(accelY); //Remove(); } private void walk(float accelY) { // TODO Auto-generated method stub direction = accelY; } private void Remove() { for (Iterator<MyContact> it1 = _contactListener.mContacts.iterator(); it1.hasNext();) { MyContact contact = it1.next(); Body bodyA = contact.fixtureA.getBody(); Body bodyB = contact.fixtureB.getBody(); // See if there's any user data attached to the Box2D body // There should be, since we set it in addBoxBodyForSprite if (bodyA.getUserData() != null && bodyB.getUserData() != null) { CCSprite spriteA = (CCSprite) bodyA.getUserData(); CCSprite spriteB = (CCSprite) bodyB.getUserData(); // Is sprite A a cat and sprite B a car? If so, push the cat // on a list to be destroyed... if (spriteA.getTag() == 1 && spriteB.getTag() == 2) { //Log.v("dsfds", "dsfsd"+bodyA); //_world.destroyBody(bodyA); // removeChild(spriteA, true); toDestroy.add(bodyA); } // Is sprite A a car and sprite B a cat? If so, push the cat // on a list to be destroyed... else if (spriteA.getTag() == 2 && spriteB.getTag() == 1) { //Log.v("dsfds", "dsfsd"+bodyB); toDestroy.add(bodyB); } } } // Loop through all of the box2d bodies we want to destroy... for (Iterator<Body> it1 = toDestroy.iterator(); it1.hasNext();) { Body body = it1.next(); // See if there's any user data attached to the Box2D body // There should be, since we set it in addBoxBodyForSprite if (body.getUserData() != null) { // We know that the user data is a sprite since we set // it that way, so cast it... CCSprite sprite = (CCSprite) body.getUserData(); // Remove the sprite from the scene _world.destroyBody(body); removeChild(sprite, true); } // Destroy the Box2D body as well // _contactListener.mContacts.remove(0); } } public synchronized void tick(float delta) { synchronized (_world) { _world.step(delta, 8, 3); //_world.clearForces(); //addNewSprite(); } CCAnimation danceAnimation = CCAnimation.animation("dance", 1.0f); // Iterate over the bodies in the physics world Iterator<Body> it = _world.getBodies(); while(it.hasNext()) { Body b = it.next(); Object userData = b.getUserData(); if (userData != null && userData instanceof CCSprite) { //Synchronize the Sprites position and rotation with the corresponding body CCSprite sprite = (CCSprite)userData; if(sprite.getTag()==1) { //b.applyLinearImpulse(force, pos); sprite.setPosition(b.getPosition().x * PTM_RATIO, b.getPosition().y * PTM_RATIO); sprite.setRotation(-1.0f * ccMacros.CC_RADIANS_TO_DEGREES(b.getAngle())); } else { //Apply the directional impulse float impulse = monkey_body.getMass()*direction*WALK_FACTOR; Vector2 force = new Vector2(impulse, 0); b.applyLinearImpulse(force, b.getWorldCenter()); sprite.setPosition(b.getPosition().x * PTM_RATIO, b.getPosition().y * PTM_RATIO); animDelay -= 1.0f/60.0f; if(animDelay <= 0) { animDelay = ANIM_SPEED; animPhase++; if(animPhase > 2) { animPhase = 1; } } if(direction < 0 ) { isLeft=1; } else { isLeft=0; } if(isLeft==1) { dir = "left"; } else { dir = "right"; } float standingLimit = (float) 0.1f; float vX = monkey_body.getLinearVelocity().x; if((vX > -standingLimit)&& (vX < standingLimit)) { // Log.v("sasd", "standing"); } else { } } } } Remove(); } } Sorry for my english. Thanks in advance.

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  • How to Create SharePoint List and Insert List Item programmatically from a Windows Forms Application.

    - by Michael M. Bangoy
    In this post I’m going to demonstrate how to create SharePoint List and also Insert Items on the List from a Windows Forms Application. 1. Open Visual Studio and create a new project. On the project template select Windows Form Application under C#. 2. In order to communicate with Sharepoint from a Windows Forms Application we need to add the 2 Sharepoint Client DLL located in c:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\ISAPI.  3. Select the Microsoft.Sharepoint.Client.dll and Microsoft.Sharepoint.Client.Runtime.dll. (Your solution should look like the one below) 4. Open the Form1 in design view and from the Toolbox menu add a button on the form surface. Your form should look like the one below. 5. Double click the button to open the code view. Add Using statement to reference the Sharepoint Client Library then create method for the Create List. Your code should like the codes below. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Security; using System.Windows.Forms; using SP = Microsoft.SharePoint.Client; namespace ClientObjectModel {     public partial class Form1 : Form     {         // url of the Sharepoint site         const string _context = "urlofthesharepointsite";         public Form1()         {             InitializeComponent();         }         private void Form1_Load(object sender, EventArgs e)         {                    }         private void cmdcreate_Click(object sender, EventArgs e)         {             try             {                 // declare the ClientContext Object                 SP.ClientContext _clientcontext = new SP.ClientContext(_context);                 SP.Web _site = _clientcontext.Web;                 // declare a ListCreationInfo                 SP.ListCreationInformation _listcreationinfo = new SP.ListCreationInformation();                 // set the Title and the Template of the List to be created                 _listcreationinfo.Title = "NewListFromCOM";                 _listcreationinfo.TemplateType = (int)SP.ListTemplateType.GenericList;                 // Call the add method to the ListCreatedInfo                 SP.List _list = _site.Lists.Add(_listcreationinfo);                 // Add Description field to the List                 SP.Field _Description = _list.Fields.AddFieldAsXml(@"                                     <Field Type='Text'                                         DisplayName='Description'>                                     </Field>", true, SP.AddFieldOptions.AddToDefaultContentType);                 // declare the List item Creation object for creating List Item                 SP.ListItemCreationInformation _itemcreationinfo = new SP.ListItemCreationInformation();                 // call the additem method of the list to insert a new List Item                 SP.ListItem _item = _list.AddItem(_itemcreationinfo);                 _item["Title"] = "New Item from Client Object Model";                 _item["Description"] = "This item was added by a Windows Forms Application";                 // call the update method                 _item.Update();                 // execute the query of the clientcontext                 _clientcontext.ExecuteQuery();                 // dispose the clientcontext                 _clientcontext.Dispose();                 MessageBox.Show("List Creation Successfull");             }             catch(Exception ex)             {                 MessageBox.Show("Error creating list" + ex.ToString());             }          }     } } 6. Hit F5 to run the application. A message will be displayed on the screen if the operation is successful and also if it fails. 7. To make that the operation of our Windows Form Application has really created the List and Inserted an item on it. Let’s open our SharePoint site. Once the SharePoint is open click on the Site Actions then View All Site Content. 7. Click the List to open it and check if an Item is inserted. That’s it. Hope this helps.

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  • Application Module Extension in Oracle Application R12

    - by Manoj Madhusoodanan
    In this blog I will describe how to Extend Application Module.I will explain this based on my previous blog PL/SQL based EO.  I want to extend FndUserAM to add a procedure to raise a custom business event when the FND_USER has created successfully. Here I am using a custom business event "xxcust.oracle.apps.demo_event". Please find the code used in Business Event. TablePackage Following steps needs to perform. 1) Download all files pertaining to "Entity Object Based on PL/SQL" to JDEV_USER_HOME/myprojects and JDEV_USER_HOME/myclasses.If you want to see the content of source java file decompile it and save it in JDEV_USER_HOME/myprojects. 2) Create XXFndUserAM as follows. 3) Add following method to XXFndUserAMImpl.    import oracle.apps.fnd.framework.OAException;   import oracle.apps.fnd.framework.server.OADBTransactionImpl;   import oracle.apps.fnd.wf.bes.BusinessEvent;   import oracle.apps.fnd.wf.bes.BusinessEventException;    import java.sql.Connection;     public void raiseEvent(String userName) {        String eventName = "xxcust.oracle.apps.demo_event";        String eventKey = userName;        Connection conn = ((OADBTransactionImpl)getOADBTransaction()).getJdbcConnection();         BusinessEvent event = null;         try{             event = new BusinessEvent(eventName, eventKey);             /* Setting Parameters */             event.setStringProperty("USER_NAME",userName);             event.setStringProperty("STATUS","User has created sucessfully");             event.raise(conn);             }             catch (BusinessEventException e) {                 throw new OAException("Exception occured when invoking web service - "+e.getMessage());             }             getOADBTransaction().commit();    } 4) Create a controller which extends from xxcust.oracle.apps.fnd.user.webui.CreateFndUserCO.Call raiseEvent method from new controller. 5) Create substitution for FndUserAM. 6) Migrate following files to $JAVA_TOP. xxcustom.oracle.apps.fnd.user.server.FndUserAMImpl.javaxxcustom.oracle.apps.fnd.user.server.XXFndUserAM.xmlxxcustom.oracle.apps.fnd.user.webui.XXCreateFndUserCO.java 8) Migrate the substitution. 9) Restart the server. 10) Personalize the page /xxcust/oracle/apps/fnd/user/webuiCreateFndUserPG and set the new controller. 11) Verify the substitution has properly applied by clicking About the Page. 12) Access the page and create a user. You can the the result of the Business Event.

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  • Oracle GoldenGate Active-Active Part 1

    - by Nick_W
    My name is Nick Wagner, and I'm a recent addition to the Oracle Maximum Availability Architecture (MAA) product management team.  I've spent the last 15+ years working on database replication products, and I've spent the last 10 years working on the Oracle GoldenGate product.  So most of my posting will probably be focused on OGG.  One question that comes up all the time is around active-active replication with Oracle GoldenGate.  How do I know if my application is a good fit for active-active replication with GoldenGate?   To answer that, it really comes down to how you plan on handling conflict resolution.  I will delve into topology and deployment in a later blog, but here is a simple architecture: The two most common resolution routines are host based resolution and timestamp based resolution. Host based resolution is used less often, but works with the fewest application changes.  Think of it like this: any transactions from SystemA always take precedence over any transactions from SystemB.  If there is a conflict on SystemB, then the record from SystemA will overwrite it.  If there is a conflict on SystemA, then it will be ignored.  It is quite a bit less restrictive, and in most cases, as long as all the tables have primary keys, host based resolution will work just fine.  Timestamp based resolution, on the other hand, is a little trickier. In this case, you can decide which record is overwritten based on timestamps. For example, does the older record get overwritten with the newer record?  Or vice-versa?  This method not only requires primary keys on every table, but it also requires every table to have a timestamp/date column that is updated each time a record is inserted or updated on the table.  Most homegrown applications can always be customized to include these requirements, but it's a little more difficult with 3rd party applications, and might even be impossible for large ERP type applications.  If your database has these features - whether it’s primary keys for host based resolution, or primary keys and timestamp columns for timestamp based resolution - then your application could be a great candidate for active-active replication.  But table structure is not the only requirement.  The other consideration applies when there is a conflict; i.e., do I need to perform any notification or track down the user that had their data overwritten?  In most cases, I don't think it's necessary, but if it is required, OGG can always create an exceptions table that contains all of the overwritten transactions so that people can be notified. It's a bit of extra work to implement this type of option, but if the business requires it, then it can be done. Unless someone is constantly monitoring this exception table or has an automated process in dealing with exceptions, there will be a delay in getting a response back to the end user. Ideally, when setting up active-active resolution we can include some simple procedural steps or configuration options that can reduce, or in some cases eliminate the potential for conflicts.  This makes the whole implementation that much easier and foolproof.  And I'll cover these in my next blog. 

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  • Is there a theory for "transactional" sequences of failing and no-fail actions?

    - by Ross Bencina
    My question is about writing transaction-like functions that execute sequences of actions, some of which may fail. It is related to the general C++ principle "destructors can't throw," no-fail property, and maybe also with multi-phase transactions or exception safety. However, I'm thinking about it in language-neutral terms. My concern is with correctly designing error handling in C++ functions that must be reliable. I would like to know what the concepts below are called so that I can learn more about them. I'm sorry that I can't ask the question more directly. Since I don't know this area I have provided an example to explain my question. The question is at the end. Here goes: Consider a sequence of steps or actions executed sequentially, where actions belong to one of two classes: those that always succeed, and those that may fail. In the examples below: S stands for an action that always succeeds (called "no-fail" in some settings). F stands for an action that may fail (for example, it might fail to allocate memory or do I/O that could fail). Consider a sequences of actions (executed sequentially from left to right): S->S->S->S Since each action in the sequence above succeeds, the whole sequence succeeds. On the other hand, the following sequence may fail because the last action may fail: S->S->S->F So, claim: a sequence has the no-fail (S) property if and only if all of its actions are no-fail. Now, I'm interested in action sequences that form "atomic transactions", with "failure atomicity," i.e. where either the whole sequence completes successfully, or there is no effect. I.e. if some action fails, the earlier ones must be rolled back. This requires that any successfully executed actions prior to a failing action must always be able to be rolled back. Consider the sequence: S->S->S->F S<-S<-S In the example above, the first row is the forward path of the transaction, and the second row are inverse actions (executed from right to left) that can be used to roll back if the final top row actions fails. It seems to me that for a transaction to support failure atomicity, the following invariant must hold: Claim: To support failure atomicity (either completion or complete roll-back on failure) all actions preceding the latest failable (F) action on the forward path (marked * in the example below) must have no-fail (S) inverses. The following is an example of a sequence that supports failure atomicity: * S->F->F->F S<-S<-S Further, if we want the transaction to be able to attempt cancellation mid-way through, but still guarantee either full completion or full rollback then we need the following property: Claim: To support failure atomicity and cancellation mid-way through execution, in the face of errors in the inverse (cancellation) path, all actions following the earliest failable (F) inverse on the reverse path (marked *) must be no-fail (S). F->F->F->S->S S<-S<-F<-F * I believe that these two conditions guarantee that an abortable/cancelable transaction will never get "stuck". My questions are: What is the study and theory of these properties called? are my claims correct? and what else is there to know? UPDATE 1: Updated terminology: what I previously called "robustness" is called atomicity in the database literature. UPDATE 2: Added explicit reference to failure atomicity, which seems to be a thing.

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  • JOGL2 test compiles, but doesn't execute - help?

    - by Chuchinyi
    I have a problem with JOGL2. My JOGL2Template.java compiles fine, but executing it results in the following error: D:\java\java\jogl>javac JOGL2Template.java <== compile ok D:\java\java\jogl>java JOGL2Template <== execute error Exception in thread "main" java.lang.ExceptionInInitializerError at javax.media.opengl.GLProfile.<clinit>(GLProfile.java:1176) at JOGL2Template.<init>(JOGL2Template.java:24) at JOGL2Template.main(JOGL2Template.java:57) Caused by: java.lang.SecurityException: no certificate for gluegen-rt.dll in D:\ java\lib\gluegen-rt-natives-windows-i586.jar at com.jogamp.common.util.JarUtil.validateCertificate(JarUtil.java:350) at com.jogamp.common.util.JarUtil.validateCertificates(JarUtil.java:324) at com.jogamp.common.util.cache.TempJarCache.validateCertificates(TempJa rCache.java:328) at com.jogamp.common.util.cache.TempJarCache.bootstrapNativeLib(TempJarC ache.java:283) at com.jogamp.common.os.Platform$3.run(Platform.java:308) at java.security.AccessController.doPrivileged(Native Method) at com.jogamp.common.os.Platform.loadGlueGenRTImpl(Platform.java:298) at com.jogamp.common.os.Platform.<clinit>(Platform.java:207) ... 3 more Here is the JOGL2Template.java source code: import java.awt.Dimension; import java.awt.Frame; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.media.opengl.GLAutoDrawable; import javax.media.opengl.GLCapabilities; import javax.media.opengl.GLEventListener; import javax.media.opengl.GLProfile; import javax.media.opengl.awt.GLCanvas; import com.jogamp.opengl.util.FPSAnimator; import javax.swing.JFrame; /* * JOGL 2.0 Program Template For AWT applications */ public class JOGL2Template extends JFrame implements GLEventListener { private static final int CANVAS_WIDTH = 640; // Width of the drawable private static final int CANVAS_HEIGHT = 480; // Height of the drawable private static final int FPS = 60; // Animator's target frames per second // Constructor to create profile, caps, drawable, animator, and initialize Frame public JOGL2Template() { // Get the default OpenGL profile that best reflect your running platform. GLProfile glp = GLProfile.getDefault(); // Specifies a set of OpenGL capabilities, based on your profile. GLCapabilities caps = new GLCapabilities(glp); // Allocate a GLDrawable, based on your OpenGL capabilities. GLCanvas canvas = new GLCanvas(caps); canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT)); canvas.addGLEventListener(this); // Create a animator that drives canvas' display() at 60 fps. final FPSAnimator animator = new FPSAnimator(canvas, FPS); addWindowListener(new WindowAdapter() { // For the close button @Override public void windowClosing(WindowEvent e) { // Use a dedicate thread to run the stop() to ensure that the // animator stops before program exits. new Thread() { @Override public void run() { animator.stop(); System.exit(0); } }.start(); } }); add(canvas); pack(); setTitle("OpenGL 2 Test"); setVisible(true); animator.start(); // Start the animator } public static void main(String[] args) { new JOGL2Template(); } @Override public void init(GLAutoDrawable drawable) { // Your OpenGL codes to perform one-time initialization tasks // such as setting up of lights and display lists. } @Override public void display(GLAutoDrawable drawable) { // Your OpenGL graphic rendering codes for each refresh. } @Override public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) { // Your OpenGL codes to set up the view port, projection mode and view volume. } @Override public void dispose(GLAutoDrawable drawable) { // Hardly used. } } Any ideas what might be the cause of these errors?

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  • RemoveHandler Issues with Custom Events

    - by Jeff Certain
    This is a case of things being more complicated that I thought they should be. Since it took a while to figure this one out, I thought it was worth explaining and putting all of the pieces to the answer in one spot. Let me set the stage. Architecturally, I have the notion of generic producers and consumers. These put items onto, and remove items from, a queue. This provides a generic, thread-safe mechanism to load balance the creation and processing of work items in our application. Part of the IProducer(Of T) interface is: 1: Public Interface IProducer(Of T) 2: Event ItemProduced(ByVal sender As IProducer(Of T), ByVal item As T) 3: Event ProductionComplete(ByVal sender As IProducer(Of T)) 4: End Interface Nothing sinister there, is there? In order to simplify our developers’ lives, I wrapped the queue with some functionality to manage the produces and consumers. Since the developer can specify the number of producers and consumers that are spun up, the queue code manages adding event handlers as the producers and consumers are instantiated. Now, we’ve been having some memory leaks and, in order to eliminate the possibility that this was caused by weak references to event handles, I wanted to remove them. This is where it got dicey. My first attempt looked like this: 1: For Each producer As P In Producers 2: RemoveHandler producer.ItemProduced, AddressOf ItemProducedHandler 3: RemoveHandler producer.ProductionComplete, AddressOf ProductionCompleteHandler 4: producer.Dispose() 5: Next What you can’t see in my posted code are the warnings this caused. The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.  Now, what on earth does that mean? Well, a quick Bing search uncovered a whole bunch of talk about delegates. The first solution I found just changed all parameters in the event handler to Object. Sorry, but no. I used generics precisely because I wanted type safety, not because I wanted to use Object. More searching. Eventually, I found this forum post, where Jeff Shan revealed a missing piece of the puzzle. The other revelation came from Lian_ZA in this post. However, these two only hinted at the solution. Trying some of what they suggested led to finally getting an invalid cast exception that revealed the existence of ItemProducedEventHandler. Hold on a minute! I didn’t create that delegate. There’s nothing even close to that name in my code… except the ItemProduced event in the interface. Could it be? Naaaaah. Hmmm…. Well, as it turns out, there is a delegate created by the compiler for each event. By explicitly creating a delegate that refers to the method in question, implicitly cast to the generated delegate type, I was able to remove the handlers: 1: For Each producer As P In Producers 2: Dim _itemProducedHandler As IProducer(Of T).ItemProducedEventHandler = AddressOf ItemProducedHandler 3: RemoveHandler producer.ItemProduced, _itemProducedHandler 4:  5: Dim _productionCompleteHandler As IProducer(Of T).ProductionCompleteEventHandler = AddressOf ProductionCompleteHandler 6: RemoveHandler producer.ProductionComplete, _productionCompleteHandler 7: producer.Dispose() 8: Next That’s “all” it took to finally be able to remove the event handlers and maintain type-safe code. Hopefully, this will save you the same challenges I had in trying to figure out how to fix this issue!

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  • Problem with creating a deterministic finite automata (DFA) - Mercury

    - by Jabba The hut
    I would like to have a deterministic finite automata (DFA) simulated in Mercury. But I’m s(t)uck at several places. Formally, a DFA is described with the following characteristics: a setOfStates S, an inputAlphabet E <-- summation symbol, a transitionFunction : S × E -- S, a startState s € S, a setOfAcceptableFinalStates F =C S. A DFA will always starts in the start state. Then the DFA will read all the characters on the input, one by one. Based on the current input character and the current state, there will be made to a new state. These transitions are defined in the transitions function. when the DFA is in one of his acceptable final states, after reading the last character, then will the DFA accept the input, If not, then the input will be is rejected. The figure shows a DFA the accepting strings where the amount of zeros, is a plurality of three. Condition 1 is the initial state, and also the only acceptable state. for each input character is the corresponding arc followed to the next state. Link to Figure What must be done A type “mystate” which represents a state. Each state has a number which is used for identification. A type “transition” that represents a possible transition between states. Each transition has a source_state, an input_character, and a final_state. A type “statemachine” that represents the entire DFA. In the solution, the DFA must have the following properties: The set of all states, the input alphabet, a transition function, represented as a set of possible transitions, a set of accepting final states, a current state of the DFA A predicate “init_machine (state machine :: out)” which unifies his arguments with the DFA, as shown as in the Figure. The current state for the DFA is set to his initial state, namely, 1. The input alphabet of the DFA is composed of the characters '0'and '1'. A user can enter a text, which will be controlled by the DFA. the program will continues until the user types Ctrl-D and simulates an EOF. If the user use characters that are not allowed into the input alphabet of the DFA, then there will be an error message end the program will close. (pred require) Example Enter a sentence: 0110 String is not ok! Enter a sentence: 011101 String is not ok! Enter a sentence: 110100 String is ok! Enter a sentence: 000110010 String is ok! Enter a sentence: 011102 Uncaught exception Mercury: Software Error: Character does not belong to the input alphabet! the thing wat I have. :- module dfa. :- interface. :- import_module io. :- pred main(io.state::di, io.state::uo) is det. :- implementation. :- import_module int,string,list,bool. 1 :- type mystate ---> state(int). 2 :- type transition ---> trans(source_state::mystate, input_character::bool, final_state::mystate). 3 (error, finale_state and current_state and input_character) :- type statemachine ---> dfa(list(mystate),list(input_character),list(transition),list(final_state),current_state(mystate)) 4 missing a lot :- pred init_machine(statemachine :: out) is det. %init_machine(statemachine(L_Mystate,0,L_transition,L_final_state,1)) :- <-probably fault 5 not perfect main(!IO) :- io.write_string("\nEnter a sentence: ", !IO), io.read_line_as_string(Input, !IO), ( Invoer = ok(StringVar), S1 = string.strip(StringVar), (if S1 = "mustbeabool" then io.write_string("Sentenceis Ok! ", !IO) else io.write_string("Sentence is not Ok!.", !IO)), main(!IO) ; Invoer = eof ; Invoer = error(ErrorCode), io.format("%s\n", [s(io.error_message(ErrorCode))], !IO) ). Hope you can help me kind regards

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  • C# 5 Async, Part 3: Preparing Existing code For Await

    - by Reed
    While the Visual Studio Async CTP provides a fantastic model for asynchronous programming, it requires code to be implemented in terms of Task and Task<T>.  The CTP adds support for Task-based asynchrony to the .NET Framework methods, and promises to have these implemented directly in the framework in the future.  However, existing code outside the framework will need to be converted to using the Task class prior to being usable via the CTP. Wrapping existing asynchronous code into a Task or Task<T> is, thankfully, fairly straightforward.  There are two main approaches to this. Code written using the Asynchronous Programming Model (APM) is very easy to convert to using Task<T>.  The TaskFactory class provides the tools to directly convert APM code into a method returning a Task<T>.  This is done via the FromAsync method.  This method takes the BeginOperation and EndOperation methods, as well as any parameters and state objects as arguments, and returns a Task<T> directly. For example, we could easily convert the WebRequest BeginGetResponse and EndGetResponse methods into a method which returns a Task<WebResponse> via: Task<WebResponse> task = Task.Factory .FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Event-based Asynchronous Pattern (EAP) code can also be wrapped into a Task<T>, though this requires a bit more effort than the one line of code above.  This is handled via the TaskCompletionSource<T> class.  MSDN provides a detailed example of using this to wrap an EAP operation into a method returning Task<T>.  It demonstrates handling cancellation and exception handling as well as the basic operation of the asynchronous method itself. The basic form of this operation is typically: Task<YourResult> GetResultAsync() { var tcs = new TaskCompletionSource<YourResult>(); // Handle the event, and setup the task results... this.GetResultCompleted += (o,e) => { if (e.Error != null) tcs.TrySetException(e.Error); else if (e.Cancelled) tcs.TrySetCanceled(); else tcs.TrySetResult(e.Result); }; // Call the asynchronous method this.GetResult(); // Return the task from the TaskCompletionSource return tcs.Task; } We can easily use these methods to wrap our own code into a method that returns a Task<T>.  Existing libraries which cannot be edited can be extended via Extension methods.  The CTP uses this technique to add appropriate methods throughout the framework. The suggested naming for these methods is to define these methods as “Task<YourResult> YourClass.YourOperationAsync(…)”.  However, this naming often conflicts with the default naming of the EAP.  If this is the case, the CTP has standardized on using “Task<YourResult> YourClass.YourOperationTaskAsync(…)”. Once we’ve wrapped all of our existing code into operations that return Task<T>, we can begin investigating how the Async CTP can be used with our own code.

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  • WiX, MSDeploy and an appealing configuration/deployment paradigm

    - by alexhildyard
    I do a lot of application and server configuration; I've done this for many years and have tended to view the complexity of this strictly in terms of the complexity of the ultimate configuration to be deployed. For example, specific APIs aside, I would tend to regard installing a server certificate as a more complex activity than, say, copying a file or adding a Registry entry.My prejudice revolved around the idea of a sequential deployment script that not only had the explicit prescription to apply a specific server configuration, but also made the implicit presumption that the server in question was in a good known state. Scripts like this fail for hundreds of reasons -- the Default Website didn't exist; the application had already been deployed; the application had already been partially deployed and failed to rollback fully, and so on. And so the problem is that the more complex the configuration activity, the more scope for error in any individual part of that activity, and therefore the greater the chance the server in question will not end up at exactly the desired configuration level.Recently I was introduced to a completely different mindset, which, for want of a better turn of phrase, I will call the "make it so" mindset. It's extremely simple both to explain and to implement. In place of the head-down, imperative script you used to use, you substitute a set of checks -- much like exception handlers -- around each configuration activity, starting with a check of the current system state. Thus the configuration logic becomes: "IF these services aren't started then start them, and IF XYZ website doesn't exist then create it, and IF these shares don't exist then create them, and IF these shares aren't permissioned in some particular way, then permission them so." This works. Really well, in my experience. Scenario 1: You want to get a system into a good known state; it's already in a good known state; you quickly realise there is nothing to do.Scenario 2: You want to get the system into a good known state; your script is flawed or the system is bust; it cannot be put into that state. You know exactly where (at least part of) the problem is and why.Scenario 3: You want to get the system into a good known state; people are fiddling around with the system just now. That's fine. You do what you can, and later you come back and try it againScenario 4: No one wants to deploy anything; they want you to prove that the previous deployment was successful. So you re-run the deployment script with the "-WhatIf" flag. It reports that there was nothing to change. There's your proof.I mentioned two technologies in the title -- MSI and MSDeploy. I am thinking specifically of the conversation that took place here. Having worked with both technologies, I think Rob Mensching's response is appropriately nuanced, and in essence the difference is this: sometimes your target is either to achieve a specific new server state, or to rollback to a known good one. Then again, your target may be to configure what you can, and to understand what you can't. Implicitly MSDeploy's "rollback" is simply to redeploy the previous version, whereas a well-crafted MSI will actively put your system into that state without further intervention. Either way, if all goes well it will leave you with a system in one of two states, whereas MSDeploy could leave your system in one of many states. The key is that MSDeploy and MSI are complementary technologies; which suits you best depends as much on Operational guidance as your Configuration remit.What I wanted to say was that I have always been for atomic, transactional-based configuration, but having worked with the "make it so" paradigm, I have been favourably impressed by the actual results. I'm tempted to put a more technical post up on this in due course.

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  • Learn Many Languages

    - by Jeff Foster
    My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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  • Omni-directional light shadow mapping with cubemaps in WebGL

    - by Winged
    First of all I must say, that I have read a lot of posts describing an usage of cubemaps, but I'm still confused about how to use them. My goal is to achieve a simple omni-directional (point) light type shading in my WebGL application. I know that there is a lot more techniques (like using Two-Hemispheres or Camera Space Shadow Mapping) which are way more efficient, but for an educational purpose cubemaps are my primary goal. Till now, I have adapted a simple shadow mapping which works with spotlights (with one exception: I don't know how to cut off the glitchy part beyond the reach of a single shadow map texture): glitchy shadow mapping<<< So for now, this is how I understand the usage of cubemaps in shadow mapping: Setup a framebuffer (in case of cubemaps - 6 framebuffers; 6 instead of 1 because every usage of framebufferTexture2D slows down an execution which is nicely described here <<<) and a texture cubemap. Also in WebGL depth components are not well supported, so I need to render it to RGBA first. this.texture = gl.createTexture(); gl.bindTexture(gl.TEXTURE_CUBE_MAP, this.texture); gl.texParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MAG_FILTER, gl.LINEAR); for (var face = 0; face < 6; face++) gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, gl.RGBA, this.size, this.size, 0, gl.RGBA, gl.UNSIGNED_BYTE, null); gl.bindTexture(gl.TEXTURE_CUBE_MAP, null); this.framebuffer = []; for (face = 0; face < 6; face++) { this.framebuffer[face] = gl.createFramebuffer(); gl.bindFramebuffer(gl.FRAMEBUFFER, this.framebuffer[face]); gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_CUBE_MAP_POSITIVE_X + face, this.texture, 0); gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, this.depthbuffer); var e = gl.checkFramebufferStatus(gl.FRAMEBUFFER); // Check for errors if (e !== gl.FRAMEBUFFER_COMPLETE) throw "Cubemap framebuffer object is incomplete: " + e.toString(); } Setup the light and the camera (I'm not sure if should I store all of 6 view matrices and send them to shaders later, or is there a way to do it with just one view matrix). Render the scene 6 times from the light's position, each time in another direction (X, -X, Y, -Y, Z, -Z) for (var face = 0; face < 6; face++) { gl.bindFramebuffer(gl.FRAMEBUFFER, shadow.buffer.framebuffer[face]); gl.viewport(0, 0, shadow.buffer.size, shadow.buffer.size); gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); camera.lookAt( light.position.add( cubeMapDirections[face] ) ); scene.draw(shadow.program); } In a second pass, calculate the projection a a current vertex using light's projection and view matrix. Now I don't know If should I calculate 6 of them, because of 6 faces of a cubemap. ScaleMatrix pushes the projected vertex into the 0.0 - 1.0 region. vDepthPosition = ScaleMatrix * uPMatrixFromLight * uVMatrixFromLight * vWorldVertex; In a fragment shader calculate the distance between the current vertex and the light position and check if it's deeper then the depth information read from earlier rendered shadow map. I know how to do it with a 2D Texture, but I have no idea how should I use cubemap texture here. I have read that texture lookups into cubemaps are performed by a normal vector instead of a UV coordinate. What vector should I use? Just a normalized vector pointing to the current vertex? For now, my code for this part looks like this (not working yet): float shadow = 1.0; vec3 depth = vDepthPosition.xyz / vDepthPosition.w; depth.z = length(vWorldVertex.xyz - uLightPosition) * linearDepthConstant; float shadowDepth = unpack(textureCube(uDepthMapSampler, vWorldVertex.xyz)); if (depth.z > shadowDepth) shadow = 0.5; Could you give me some hints or examples (preferably in WebGL code) how I should build it?

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  • I am trying to create an windows application watcher? [migrated]

    - by Broken_Code
    I recently started coding in c #(in may this year) and well I find it best to learn by working with code. this application http://www.c-sharpcorner.com/UploadFile/satisharveti/ActiveApplicationWatcher01252007024921AM/ActiveApplicationWatcher.aspx. I am trying to recreate it however mine will be saving the information into an sql database(new at this as well). I am having some coding problems though as it does not do what I expect it to do. THis is the main code I am using. private void GetTotalTimer() { DateTime now = DateTime.Now; IntPtr hwnd = APIFunc.getforegroundWindow(); Int32 pid = APIFunc.GetWindowProcessID(hwnd); Process p = Process.GetProcessById(pid); appName = p.ProcessName; const int nChars = 256; int handle = 0; StringBuilder Buff = new StringBuilder(nChars); handle = GetForegroundWindow(); appltitle = APIFunc.ActiveApplTitle().Trim().Replace("\0", ""); //if (GetWindowText(handle, Buff, nChars) > 0) //{ // string strbuff = Buff.ToString(); // StrWindow = strbuff; #region insert statement try { if (Conn.State == ConnectionState.Closed) { Conn.Open(); } if (Conn.State == ConnectionState.Open) { SqlCommand com = new SqlCommand("Select top 1 [Window Title] From TimerLogs ORDER BY [Time of Event] DESC", Conn); SqlDataReader reader = com.ExecuteReader(); startTime = DateTime.Now; string time = now.ToString(); if (!reader.HasRows) { reader.Close(); cmd = new SqlCommand("insert into [TimerLogs] values(@time,@appName,@appltitle,@Elapsed_Time,@userName)", Conn); cmd.Parameters.AddWithValue("@time", time); cmd.Parameters.AddWithValue("@appName", appName); cmd.Parameters.AddWithValue("@appltitle", appltitle); cmd.Parameters.AddWithValue("@Elapsed_Time", blank.ToString()); cmd.Parameters.AddWithValue("@userName", userName); cmd.ExecuteNonQuery(); Conn.Close(); } else if(reader.HasRows) { reader.Read(); if (appltitle != reader.ToString()) { reader.Close(); endTime = DateTime.Now; appduration = endTime.Subtract(startTime); cmd = new SqlCommand("insert into [TimerLogs] values (@time,@appName,@appltitle,@Elapsed_Time,@userName)", Conn); cmd.Parameters.AddWithValue("@time", time); cmd.Parameters.AddWithValue("@appName", appName); cmd.Parameters.AddWithValue("@appltitle", appltitle); cmd.Parameters.AddWithValue("@Elapsed_Time", appduration.ToString()); cmd.Parameters.AddWithValue("@userName", userName); cmd.ExecuteNonQuery(); reader.Close(); Conn.Close(); } } } } catch (Exception) { } //} #endregion ActivityTimer.Start(); Processing = "Working"; } Unfortunately this is the result. it is not saving the data as I expect it to. What am i doing wrong I had thought that with the sql reader it would first check for a value and only save if they do not match however it is saving whether there is a match or not.

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  • Missing Fields and Default Values

    - by PointsToShare
    © 2011 By: Dov Trietsch. All rights reserved Dealing with Missing Fields and Default Values New fields and new default values are not propagated throughout the list. They only apply to new and updated items and not to items already entered. They are only prospective. We need to be able to deal with this issue. Here is a scenario. The user has an old list with old items and adds a new field. The field is not created for any of the old items. Trying to get its value raises an Argument Exception. Here is another: a default value is added to a field. All the old items, where the field was not assigned a value, do not get the new default value. The two can also happen in tandem – a new field is added with a default. The older items have neither. Even better, if the user changes the default value, the old items still carry the old defaults. Let’s go a bit further. You have already written code for the list, be it an event receiver, a feature receiver, a console app or a command extension, in which you span all the fields and run on selected items – some new (no problem) and some old (problems aplenty). Had you written defensive code, you would be able to handle the situation, including similar changes in the future. So, without further ado, here’s how. Instead of just getting the value of a field in an item – item[field].ToString() – use the function below. I use ItemValue(item, fieldname, “mud in your eye”) and if “mud in your eye” is what I get, I know that the item did not have the field.   /// <summary> /// Return the column value or a default value /// </summary> private static string ItemValue(SPItem item, string column, string defaultValue) {     try     {         return item[column].ToString();     }     catch (NullReferenceException ex)     {         return defaultValue;     }     catch (ArgumentException ex)     {         return defaultValue;     } } I also use a similar function to return the default and a funny default-default to ascertain that the default does not exist. Here it is:  /// <summary> /// return a fields default or the "default" default. /// </summary> public static string GetFieldDefault(SPField fld, string defValue) {     try     {         // -- Check if default exists.         return fld.DefaultValue.ToString();     }     catch (NullReferenceException ex)     {         return defValue;     }     catch (ArgumentException ex)     {         return defValue;     } } How is this defensive? You have trapped an expected error and dealt with it. Therefore the program did not stop cold in its track and the required code ran to its end. Now, take a further step - write to a log (See Logging – a log blog). Read your own log every now and then, and act accordingly. That’s all Folks!

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  • The long road to bug-free software

    - by Tony Davis
    The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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  • Dynamically load and call delegates based on source data

    - by makerofthings7
    Assume I have a stream of records that need to have some computation. Records will have a combination of these functions run Sum, Aggregate, Sum over the last 90 seconds, or ignore. A data record looks like this: Date;Data;ID Question Assuming that ID is an int of some kind, and that int corresponds to a matrix of some delegates to run, how should I use C# to dynamically build that launch map? I'm sure this idea exists... it is used in Windows Forms which has many delegates/events, most of which will never actually be invoked in a real application. The sample below includes a few delegates I want to run (sum, count, and print) but I don't know how to make the quantity of delegates fire based on the source data. (say print the evens, and sum the odds in this sample) using System; using System.Threading; using System.Collections.Generic; internal static class TestThreadpool { delegate int TestDelegate(int parameter); private static void Main() { try { // this approach works is void is returned. //ThreadPool.QueueUserWorkItem(new WaitCallback(PrintOut), "Hello"); int c = 0; int w = 0; ThreadPool.GetMaxThreads(out w, out c); bool rrr =ThreadPool.SetMinThreads(w, c); Console.WriteLine(rrr); // perhaps the above needs time to set up6 Thread.Sleep(1000); DateTime ttt = DateTime.UtcNow; TestDelegate d = new TestDelegate(PrintOut); List<IAsyncResult> arDict = new List<IAsyncResult>(); int count = 1000000; for (int i = 0; i < count; i++) { IAsyncResult ar = d.BeginInvoke(i, new AsyncCallback(Callback), d); arDict.Add(ar); } for (int i = 0; i < count; i++) { int result = d.EndInvoke(arDict[i]); } // Give the callback time to execute - otherwise the app // may terminate before it is called //Thread.Sleep(1000); var res = DateTime.UtcNow - ttt; Console.WriteLine("Main program done----- Total time --> " + res.TotalMilliseconds); } catch (Exception e) { Console.WriteLine(e); } Console.ReadKey(true); } static int PrintOut(int parameter) { // Console.WriteLine(Thread.CurrentThread.ManagedThreadId + " Delegate PRINTOUT waited and printed this:"+parameter); var tmp = parameter * parameter; return tmp; } static int Sum(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static int Count(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static void Callback(IAsyncResult ar) { TestDelegate d = (TestDelegate)ar.AsyncState; //Console.WriteLine("Callback is delayed and returned") ;//d.EndInvoke(ar)); } }

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  • Data breakpoints to find points where data gets broken

    - by raccoon_tim
    When working with a large code base, finding reasons for bizarre bugs can often be like finding a needle in a hay stack. Finding out why an object gets corrupted without no apparent reason can be quite daunting, especially when it seems to happen randomly and totally out of context. Scenario Take the following scenario as an example. You have defined the a class that contains an array of characters that is 256 characters long. You now implement a method for filling this buffer with a string passed as an argument. At this point you mistakenly expect the buffer to be 256 characters long. At some point you notice that you require another character buffer and you add that after the previous one in the class definition. You now figure that you don’t need the 256 characters that the first member can hold and you shorten that to 128 to conserve space. At this point you should start thinking that you also have to modify the method defined above to safeguard against buffer overflow. It so happens, however, that in this not so perfect world this does not cross your mind. Buffer overflow is one of the most frequent sources for errors in a piece of software and often one of the most difficult ones to detect, especially when data is read from an outside source. Many mass copy functions provided by the C run-time provide versions that have boundary checking (defined with the _s suffix) but they can not guard against hard coded buffer lengths that at some point get changed. Finding the bug Getting back to the scenario, you’re now wondering why does the second string get modified with data that makes no sense at all. Luckily, Visual Studio provides you with a tool to help you with finding just these kinds of errors. It’s called data breakpoints. To add a data breakpoint, you first run your application in debug mode or attach to it in the usual way, and then go to Debug, select New Breakpoint and New Data Breakpoint. In the popup that opens, you can type in the memory address and the amount of bytes you wish to monitor. You can also use an expression here, but it’s often difficult to come up with an expression for data in an object allocated on the heap when not in the context of a certain stack frame. There are a couple of things to note about data breakpoints, however. First of all, Visual Studio supports a maximum of four data breakpoints at any given time. Another important thing to notice is that some C run-time functions modify memory in kernel space which does not trigger the data breakpoint. For instance, calling ReadFile on a buffer that is monitored by a data breakpoint will not trigger the breakpoint. The application will now break at the address you specified it to. Often you might immediately spot the issue but the very least this feature can do is point you in the right direction in search for the real reason why the memory gets inadvertently modified. Conclusions Data breakpoints are a great feature, especially when doing a lot of low level operations where multiple locations modify the same data. With the exception of some special cases, like kernel memory modification, you can use it whenever you need to check when memory at a certain location gets changed on purpose or inadvertently.

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  • Generic Adjacency List Graph implementation

    - by DmainEvent
    I am trying to come up with a decent Adjacency List graph implementation so I can start tooling around with all kinds of graph problems and algorithms like traveling salesman and other problems... But I can't seem to come up with a decent implementation. This is probably because I am trying to dust the cobwebs off my data structures class. But what I have so far... and this is implemented in Java... is basically an edgeNode class that has a generic type and a weight-in the event the graph is indeed weighted. public class edgeNode<E> { private E y; private int weight; //... getters and setters as well as constructors... } I have a graph class that has a list of edges a value for the number of Vertices and and an int value for edges as well as a boolean value for whether or not it is directed. The brings up my first question, if the graph is indeed directed, shouldn't I have a value in my edgeNode class? Or would I just need to add another vertices to my LinkedList? That would imply that a directed graph is 2X as big as an undirected graph wouldn't it? public class graph { private List<edgeNode<?>> edges; private int nVertices; private int nEdges; private boolean directed; //... getters and setters as well as constructors... } Finally does anybody have a standard way of initializing there graph? I was thinking of reading in a pipe-delimited file but that is so 1997. public graph GenereateGraph(boolean directed, String file){ List<edgeNode<?>> edges; graph g; try{ int count = 0; String line; FileReader input = new FileReader("C:\\Users\\derekww\\Documents\\JavaEE Projects\\graphFile"); BufferedReader bufRead = new BufferedReader(input); line = bufRead.readLine(); count++; edges = new ArrayList<edgeNode<?>>(); while(line != null){ line = bufRead.readLine(); Object edgeInfo = line.split("|")[0]; int weight = Integer.parseInt(line.split("|")[1]); edgeNode<String> e = new edgeNode<String>((String) edges.add(e); } return g; } catch(Exception e){ return null; } } I guess when I am adding edges if boolean is true I would be adding a second edge. So far, this all depends on the file I write. So if I wrote a file with the following Vertices and weights... Buffalo | 18 br Pittsburgh | 20 br New York | 15 br D.C | 45 br I would obviously load them into my list of edges, but how can I represent one vertices connected to the other... so on... I would need the opposite vertices? Say I was representing Highways connected to each city weighted and un-directed (each edge is bi-directional with weights in some fictional distance unit)... Would my implementation be the best way to do that? I found this tutorial online Graph Tutorial that has a connector object. This appears to me be a collection of vertices pointing to each other. So you would have A and B each with there weights and so on, and you would add this to a list and this list of connectors to your graph... That strikes me as somewhat cumbersome and a little dismissive of the adjacency list concept? Am I wrong and that is a novel solution? This is all inspired by steve skiena's Algorithm Design Manual. Which I have to say is pretty good so far. Thanks for any help you can provide.

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  • Using data input from pop-up page to current with partial refresh

    - by dpDesignz
    I'm building a product editor webpage using visual C#. I've got an image uploader popping up using fancybox, and I need to get the info from my fancybox once submitted to go back to the first page without clearing any info. I know I need to use ajax but how would I do it? <%@ Page Language="C#" AutoEventWireup="true" CodeFile="uploader.aspx.cs" Inherits="uploader" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title></title> </head> <body style="width:350px; height:70px;"> <form id="form1" runat="server"> <asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager> <div> <div style="width:312px; height:20px; background-color:Gray; color:White; padding-left:8px; margin-bottom:4px; text-transform:uppercase; font-weight:bold;">Uploader</div> <asp:FileUpload id="fileUp" runat="server" /> <asp:Button runat="server" id="UploadButton" text="Upload" onclick="UploadButton_Click" /> <br /><asp:Label ID="txtFile" runat="server"></asp:Label> <div style="width:312px; height:15px; background-color:#CCCCCC; color:#4d4d4d; padding-right:8px; margin-top:4px; text-align:right; font-size:x-small;">Click upload to insert your image into your product</div> </div> </form> </body> </html> CS so far using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Configuration; // Add to page using System.Web.UI; using System.Web.UI.WebControls; using System.Data; // Add to the page using System.Data.SqlClient; // Add to the page using System.Text; // Add to Page public partial class uploader : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void UploadButton_Click(object sender, EventArgs e) { if (fileUp.HasFile) try { fileUp.SaveAs("\\\\london\\users\\DP006\\Websites\\images\\" + fileUp.FileName); string imagePath = fileUp.PostedFile.FileName; } catch (Exception ex) { txtFile.Text = "ERROR: " + ex.Message.ToString(); } finally { } else { txtFile.Text = "You have not specified a file."; } } }

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  • Executing Stored Procedures in Visual Studio LightSwitch.

    - by dataintegration
    A LightSwitch Project is very easy way to visualize and manipulate information directly from one of our ADO.NET Providers. But when it comes to executing the Stored Procedures, it can be a bit more complicated. In this article, we will demonstrate how to execute a Stored Procedure in LightSwitch. For the purposes of this article, we will be using the RSSBus Email Data Provider, but the same process will work with any of our ADO.NET Providers. Creating the RIA Service. Step 1: Open Visual Studio and create a new WCF RIA Service Class Project. Step 2:Add the reference to the RSSBus Email Data Provider dll in the (ProjectName).Web project. Step 3: Add a new Domain Service Class to the (ProjectName).Web project. Step 4: In the new Domain Service Class, create a new class with the attributes needed for the Stored Procedure's parameters. In this demo, the Stored Procedure we are executing is called SendMessage. The parameters we will need are as follows: public class NewMessage{ [Key] public int ID { get; set; } public string FromEmail { get; set; } public string ToEmail { get; set; } public string Subject { get; set; } public string Text { get; set; } } Note: The created class must have an ID which will serve as the key value. Step 5: Create a new method that will executed when the insert event fires. Inside this method you can use the standards ADO.NET code which will execute the stored procedure. [Insert] public void SendMessage(NewMessage newMessage) { try { EmailConnection conn = new EmailConnection(connectionString); EmailCommand comm = new EmailCommand("SendMessage", conn); comm.CommandType = System.Data.CommandType.StoredProcedure; if (!newMessage.FromEmail.Equals("")) comm.Parameters.Add(new EmailParameter("@From", newMessage.FromEmail)); if (!newMessage.ToEmail.Equals("")) comm.Parameters.Add(new EmailParameter("@To", newMessage.ToEmail)); if (!newMessage.Subject.Equals("")) comm.Parameters.Add(new EmailParameter("@Subject", newMessage.Subject)); if (!newMessage.Text.Equals("")) comm.Parameters.Add(new EmailParameter("@Text", newMessage.Text)); comm.ExecuteNonQuery(); } catch (Exception exc) { Console.WriteLine(exc.Message); } } Step 6: Create a query method. We are not going to be using getNewMessages(), so it does not matter what it returns for the purpose of our example, but you will need to create a method for the query event as well. [Query(IsDefault=true)] public IEnumerable<NewMessage> getNewMessages() { return null; } Step 7: Rebuild the whole solution. Creating the LightSwitch Project. Step 8: Open Visual Studio and create a new LightSwitch Application Project. Step 9: On the Data Sources, add a new data source. Choose a WCF RIA Service Step 10: Choose to add a new reference and select the (Project Name).Web.dll generated from the RIA Service. Step 11: Select the entities you would like to import. In this case, we are using the recently created NewMessage entity. Step 13: On the Screens section, create a new screen and select the NewMessage entity as the Screen Data. Step 14: After you run the project, you will be able to add a new record and save it. This will execute the Stored Procedure and send the new message. If you create a screen to check the sent messages, you can refresh this screen to see the mail you sent. Sample Project To help you with get started using stored procedures in LightSwitch, download the fully functional sample project. You will also need the RSSBus Email Data Provider to make the connection. You can download a free trial here.

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  • Custom Text and Binary Payloads using WebSocket (TOTD #186)

    - by arungupta
    TOTD #185 explained how to process text and binary payloads in a WebSocket endpoint. In summary, a text payload may be received as public void receiveTextMessage(String message) {    . . . } And binary payload may be received as: public void recieveBinaryMessage(ByteBuffer message) {    . . .} As you realize, both of these methods receive the text and binary data in raw format. However you may like to receive and send the data using a POJO. This marshaling and unmarshaling can be done in the method implementation but JSR 356 API provides a cleaner way. For encoding and decoding text payload into POJO, Decoder.Text (for inbound payload) and Encoder.Text (for outbound payload) interfaces need to be implemented. A sample implementation below shows how text payload consisting of JSON structures can be encoded and decoded. public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> {     private JsonObject jsonObject;    @Override    public MyMessage decode(String string) throws DecodeException {        this.jsonObject = new JsonReader(new StringReader(string)).readObject();               return this;    }     @Override    public boolean willDecode(String string) {        return true;    }     @Override    public String encode(MyMessage myMessage) throws EncodeException {        return myMessage.jsonObject.toString();    } public JsonObject getObject() { return jsonObject; }} In this implementation, the decode method decodes incoming text payload to MyMessage, the encode method encodes MyMessage for the outgoing text payload, and the willDecode method returns true or false if the message can be decoded. The encoder and decoder implementation classes need to be specified in the WebSocket endpoint as: @WebSocketEndpoint(value="/endpoint", encoders={MyMessage.class}, decoders={MyMessage.class}) public class MyEndpoint { public MyMessage receiveMessage(MyMessage message) { . . . } } Notice the updated method signature where the application is working with MyMessage instead of the raw string. Note that the encoder and decoder implementations just illustrate the point and provide no validation or exception handling. Similarly Encooder.Binary and Decoder.Binary interfaces need to be implemented for encoding and decoding binary payload. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • why my code still cannot connect with database? [closed]

    - by Wen Teng
    package com.mems.travis; import java.util.ArrayList; import java.util.List; import org.apache.http.NameValuePair; import org.apache.http.message.BasicNameValuePair; import org.json.JSONObject; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.AsyncTask; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.RadioButton; public class UserRegister extends Activity { JSONParser jsonParser = new JSONParser(); EditText inputName; EditText inputUsername; EditText inputEmail; EditText inputPassword; RadioButton button1; RadioButton button2; Button button3; int success = 0; // url to create new product private static String url_register_user = "http://192.168.1.100/MEMS/add_user.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_user_register); // Edit Text inputName = (EditText) findViewById(R.id.nameTextBox); inputUsername = (EditText) findViewById(R.id.usernameTextBox); inputEmail = (EditText) findViewById(R.id.emailTextBox); inputPassword = (EditText) findViewById(R.id.pwTextBox); // Create button //RadioButton button1 = (RadioButton) findViewById(R.id.studButton); // RadioButton button2 = (RadioButton) findViewById(R.id.shopownerButton); Button button3 = (Button) findViewById(R.id.regSubmitButton); // button click event button3.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { String name = inputName.getText().toString(); String username = inputUsername.getText().toString(); String email = inputEmail.getText().toString(); String password = inputPassword.getText().toString(); if (name.contentEquals("")||username.contentEquals("")||email.contentEquals("")||password.contentEquals("")) { AlertDialog.Builder builder = new AlertDialog.Builder(UserRegister.this); // 2. Chain together various setter methods to set the dialog characteristics builder.setMessage(R.string.nullAlert) .setTitle(R.string.alertTitle); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User clicked OK button } }); // 3. Get the AlertDialog from create() AlertDialog dialog = builder.show(); } else { new RegisterNewUser().execute(); } } }); } class RegisterNewUser extends AsyncTask<String, String, String>{ protected String doInBackground(String... args) { String name = inputName.getText().toString(); String username = inputUsername.getText().toString(); String email = inputEmail.getText().toString(); String password = inputPassword.getText().toString(); // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("name", name)); params.add(new BasicNameValuePair("username", username)); params.add(new BasicNameValuePair("email", email)); params.add(new BasicNameValuePair("password", password)); // getting JSON Object // Note that create product url accepts POST method JSONObject json = jsonParser.makeHttpRequest(url_register_user, "GET", params); // check log cat for response Log.d("Send Notification", json.toString()); try { int success = json.getInt(TAG_SUCCESS); if (success == 1) { // successfully created product Intent i = new Intent(getApplicationContext(), StudentLogin.class); startActivity(i); finish(); } else { // failed to register } } catch (Exception e) { e.printStackTrace(); } return null; } } }

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  • Is this over-abstraction? (And is there a name for it?)

    - by mwhite
    I work on a large Django application that uses CouchDB as a database and couchdbkit for mapping CouchDB documents to objects in Python, similar to Django's default ORM. It has dozens of model classes and a hundred or two CouchDB views. The application allows users to register a "domain", which gives them a unique URL containing the domain name that gives them access to a project whose data has no overlap with the data of other domains. Each document that is part of a domain has its domain property set to that domain's name. As far as relationships between the documents go, all domains are effectively mutually exclusive subsets of the data, except for a few edge cases (some users can be members of more than one domain, and there are some administrative reports that include all domains, etc.). The code is full of explicit references to the domain name, and I'm wondering if it would be worth the added complexity to abstract this out. I'd also like to know if there's a name for the sort of bound property approach I'm taking here. Basically, I have something like this in mind: Before in models.py class User(Document): domain = StringProperty() class Group(Document): domain = StringProperty() name = StringProperty() user_ids = StringListProperty() # method that returns related document set def users(self): return [User.get(id) for id in self.user_ids] # method that queries a couch view optimized for a specific lookup @classmethod def by_name(cls, domain, name): # the view method is provided by couchdbkit and handles # wrapping json CouchDB results as Python objects, and # can take various parameters modifying behavior return cls.view('groups/by_name', key=[domain, name]) # method that creates a related document def get_new_user(self): user = User(domain=self.domain) user.save() self.user_ids.append(user._id) return user in views.py: from models import User, Group # there are tons of views like this, (request, domain, ...) def create_new_user_in_group(request, domain, group_name): group = Group.by_name(domain, group_name)[0] user = User(domain=domain) user.save() group.user_ids.append(user._id) group.save() in group/by_name/map.js: function (doc) { if (doc.doc_type == "Group") { emit([doc.domain, doc.name], null); } } After models.py class DomainDocument(Document): domain = StringProperty() @classmethod def domain_view(cls, *args, **kwargs): kwargs['key'] = [cls.domain.default] + kwargs['key'] return super(DomainDocument, cls).view(*args, **kwargs) @classmethod def get(cls, *args, **kwargs, validate_domain=True): ret = super(DomainDocument, cls).get(*args, **kwargs) if validate_domain and ret.domain != cls.domain.default: raise Exception() return ret def models(self): # a mapping of all models in the application. accessing one returns the equivalent of class BoundUser(User): domain = StringProperty(default=self.domain) class User(DomainDocument): pass class Group(DomainDocument): name = StringProperty() user_ids = StringListProperty() def users(self): return [self.models.User.get(id) for id in self.user_ids] @classmethod def by_name(cls, name): return cls.domain_view('groups/by_name', key=[name]) def get_new_user(self): user = self.models.User() user.save() views.py @domain_view # decorator that sets request.models to the same sort of object that is returned by DomainDocument.models and removes the domain argument from the URL router def create_new_user_in_group(request, group_name): group = request.models.Group.by_name(group_name) user = request.models.User() user.save() group.user_ids.append(user._id) group.save() (Might be better to leave the abstraction leaky here in order to avoid having to deal with a couchapp-style //! include of a wrapper for emit that prepends doc.domain to the key or some other similar solution.) function (doc) { if (doc.doc_type == "Group") { emit([doc.name], null); } } Pros and Cons So what are the pros and cons of this? Pros: DRYer prevents you from creating related documents but forgetting to set the domain. prevents you from accidentally writing a django view - couch view execution path that leads to a security breach doesn't prevent you from accessing underlying self.domain and normal Document.view() method potentially gets rid of the need for a lot of sanity checks verifying whether two documents whose domains we expect to be equal are. Cons: adds some complexity hides what's really happening requires no model modules to have classes with the same name, or you would need to add sub-attributes to self.models for modules. However, requiring project-wide unique class names for models should actually be fine because they correspond to the doc_type property couchdbkit uses to decide which class to instantiate them as, which should be unique. removes explicit dependency documentation (from group.models import Group)

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